Radio range



May 30, 1944 D. G. c. LUCK 2,350,284

RADIO-RANGE Filed March 3l, 1942 ,if i? Z2 l@ Grim-neu Patented May 30, 1944 UNITED ST RADIO RANGE.

David- G. C. Luck,` Merohant-ville,` N. I., assigner to Radio Corporation of America, a corporation of Delaware Application March 31, 1942, Serial No. 436,933

('Cl. Z50-11) 6 Claims.

This invention relates to radio ranges, and more particularly tocourse and quadrant identifcations in ak four-course simultaneous range. In U. S. Patent No. 2,314,795 granted to D. G. C. Luck on March` 23-, 1943, and entitled Radio ranges, systems of quadrant identification for four-course ranges. by means of phase reference modulationl were described. Application Serial No. 436,430, filed by` D. G. C. Luck on March 2'7, 1942, and entitled Radio ranges, describes a reference phase` generator providing a tone definitely related in phase to the course tone but at an odd integral harmonic or subharmonic frequency.

An object of the present invention is the provision of means for identifying the courses and quadrants of a radio range in which a special reference tone is non-directionally radiated. Another object of the invention is the provision of ay device for connection to the output of a mobile range receiver which will give a direct visual quadrant identification. A further object is the provision of a method of identifying the courses and quadrants of a four course radio range.

The invention will be described with reference tothe accompanying` drawing, of which Fig. 1 is a graph of a radio range pattern; Fig. 2 is a schematic block diagram of the device of the invention; and Fig. 3 is a schematic block diagram of a modification of. the invention.

Referring to Fig. 1, the equisignal courses I, II, III and IV are indicated at the lines along which a receiver will pick up Signals A and N with equal intensity from the range transmitters. The directive radiation patterns of the range antennas are illustrated as overlapping figuresofeight with lobes of' opposite polarities, arbitrarily designated as positive and negative. In the usual four-course simultaneous range, a non-directional antenna is used to radiate a carrier, which may be modulated with speech, or in the present instance, with a reference tone. The sidebands,` modulated at 1020 cycles per second, the so-called course tone, are directionally radiated by the range antennas and keyed by interlocking A and N signals respectively as indicated in Fig. 1. As described in the aforementioned patent, the non-directional carrier may be modulated with a reference tone related in phase and frequency to the course tone for providing an indication to the operator of` a receiving station of the course or quadrant in which the receiving station is located.

With a range set up for a reference tone of one-third the frequency of the course tone, the transmitter phases may be adjusted so that a course tone peak occurs simultaneously with a reference tone peak in the pattern lobes marked plus while a course tone trough coincides with the reference tone peak in the lobes marked minus in Fig. 1. The function of the device of the invention is then to actuate an indicator in accordance with the phase relationship between the coursel and reference tones to show the course or quadrant in which the receiver lies.

Referring to Fig. 2, the output terminals of a range receiver are connected through a filter 1, adjusted to passthe course tone which in the usual installation is 1020 cycles per second, to a limiter 33, thence through a second course tone filter 35 to the primaries 3l and 4l of a pair of transformers 5l and 53. The range receiver out put is also connected through an adjustable phase shifter 5 and a lter 2l adjusted to pass the reference tone which in this case is one third the frequency of the course tone, or 340 cycles per second, to a limiter 29, thence through a 1020 cycle pass filter 3l to the primaries 39 and i3 of the transformers 5I and 53. Voltage responsive indicator devices, such as neon lamps 45 and 4T, are connected across the secondaries of the transformers 5l and 53, respectively.

The operation of the device is as follows: The 1020 cycle course tone is separated from the receiver `output by the filter "l, and limited to a constant peak amplitude by the limiter 33. Since the limiting operation clips off the peaks of the waves, the limiter output is non-sinusoidal, but contains harmonics of the original 1020 cycle wave., The harmonics are removed by the 1020 cycle filter 35, resulting in a substantially constant amplitude 1020 cycle sine wave, related in phase,Y or more properly speaking, in polarity, to the predetermined polarity of the range quad rant in which the apparatus is located.

The 340 cycle reference phase voltage is separated from the receiver output by the filter 21', and limited to a constant amplitude by the limiter 29. The non-sinusoidal output of the limiter 29 contains a third, or 1020 cycle harmonic of the 340 cycle reference Wave. This harmonic component is separated from the limiter output by the lter 3l. This third harmonic voltage remains in `constant phase, since it is derived from the 340 cycle reference phase modulation of the non-directional range transmitter. The phase control 25 is merely used as an initial adjustment for compensating phase shifts inherent in the range receiver and filters, and once adjusted 2j requires no further attention as long as the Vsame receiver is used.

The constant phase constant amplitude third harmonic voltage from the lter 3I is applied to the primaries 39 and 43 of the transformers 5I and 53, respectively, in opposite polarities as indicated in Fig. 2; the constant amplitude voltage from the fllter'35 is applied to the primaries' 31 and 4I of the transformers 5I and 53 in the same polarity. 'I'hus when the two 1020 cycle voltages derived from the course tone and ref-` erence tone are in phase, their effects will add in one of the transformers and subtract inthe other; when they are 180 out of phase, lthey will subtract in the first transformer and add in the second. 'These conditions correspondn to positions of the range. receiver in positive and negative quadrants, respectively, of the range. j Assuming the connections to be such that the' in-phase voltages will. add in the transformer 5I and subtract inthe transformer y53, the neon lamp 45 v.will ash when the two 1020 cycle voltages are inv phase, corresponding to a location `of the receiver in one of the positive v quadrants illustrated in Fig. l. ilarly, the lamp 41 will flash when the receiver is in one of the negative quadrants. The A Vand N keying of the course tone will .cause the visual indications to flashV accordingly, soV that if the receiver Vis in a positive .A lobe the lamp '45 will iiashA inv anegative A lobe the lamp 41 will flash A, andso on. When the vreceiver is ly ing in one ofthe course lines, the operation of eachlamp is similarly related to the polarity and keying of the two overlapping lobes defining the course line. Thus,` along the course markedI,

Sim-

the; lamp 45 will-be actuated by both the A and N keying, and so will give asteady indication,

Vwhile the lamp 41 gives none. Along course II..

`the-,positive lamp 45 flashes A, while the negative lamp 41 flashes N.

. y Referring to Fig. 3, the output terminals of the rangev receiver are connected to the primary of a transformer I', provided with two secondary windings 3 and 5. The secondary 3 is connected through a filter 1 to the input of an amplifier 9, which is preferably designed to act as a limiter.

The filter 1 is adjusted to pass .the `1020 cycle vof `the transformer I is connected through an ad- .iustable phase shifting network 25 and a filter 21 to a limiter 2 9. The filter-21 is designed to passvthelO` cycle reference tone. The limiter 29 clips off the peaksof the 340 cycle voltage, producing a substantially square wave form conuniquely related to the relative polarites of the two 1020 cycle voltages and hence to the quadrant in which the range receiver is located. For

example, suppose that the circuit is so arranged that output of the amplifier 9 to the transformer Il .is in phase` with the `input to the amplifier. Then since the amplifier provides a push-pull output, the voltage produced by the amplifier across the primary of the transformer I3 is 180 degrees ,out of phase with the input.

Now if the 1020- cycle third harmonic voltage is in phase with the course tone input to the amplifier 9, it will addv Vto the amplifier output in the transformer .II and subtract fromthe amplier output in the transformer I3. Thus the voltage applied to the rectifier I5 will be greater than that appliedgto the rectifier I1, which latter may in factbe zero ifthe apparatus is adjusted so that the two 1020 cyclev voltages are of equal amplitudes in the primaries of the:transformers II and I3. The limiting characteristic of.4 the ampiifierfSf mentioned above makesV it unnecessary to adjust the amplitudes ofthe two1020 cycle voltagesfor different amplitudesof ,receiver output. Thecontrol electrode I9 of theindcator 23` will then be Venergized causing a visual Vindication tovbegdisplayed by the ,corresponding section of the target 24 in the well known manner, while the electrode 2l will not operate. Similarly, the .flower section of the target will be .causedto indicate when the two 1020-cycle voltages are out ofphase, core responding toa locationy of the receiver inzone of the negative quadrants illustratedinFig-.fll

The indications of theupper andlower sections of the tube 2 3 correspond to the courses and quadf rants "of the range in the same manner as the flashes of the indicators 45'and 4'I'ofFg. 2.

The .illustrated devices may be modified in Ymany'ways'fwitl'iout departing Yfrom thev spirit of the invention; for example, the filter 35 of Fig'. 2

maybe omitted, resulting inv less complete cancellation of the bucking 1020 cycle waves, 'butnot vseriously affecting the operation of the device when neon tube indicatorsv are used, since such indicators will notA iiash `until a comparatively high voltage is applied.l Ihe amplifier 9. of Fig. 3

might be replaced by a balanced modulator, and the tectiners` 5am-n omitted, without-changing` the operation; sincey the balanced modulator would be s"elf`rectifying. V f' t Thus vthe invention has been describedA asa de.-

. vice which utilizes the usual directionallylradi;

` non-directionally radiated. harmonically relatedV taining strong o-ddharmonics. of the S40-cycle v.

inputfThe thirdharmonic, at 1020 cycles per second, is Aselected by a filter 3|. The third harmonic voltage, which is of constant phase as explained previously, from the filter 3| is applied lin series with the plate voltage supplyyto the push-pull output tubes of theamplier 9, through the primaries of the transformers Illand I3..

l`The 1020-cycle coursetone isadded to and sub'.- `tracted from vthe- 102 0 cycl t el constant phase third harmonic of the reference tone. 3The resultant xoutputs at the transformers I I` and I3 are then ated course `tone modulation of a' simultaneous four course radio1 range, together with a special reference tonaftofgive 'a visual course and quadfrant identification," This ris '.accomplishedfby comparingthe phase orpolarity ofthe course tone with thatof the` constant phase reference tone and actuating.V an .indicator accordingly.`

I claimas'm'yinv'enti'on: I 1. A visual course andA quadrantidentification `device-[for] a1 four course simultaneous radio rangeincluding in combination a radio receiver, filters 'for separating two harmonically related modulation components vin ,thle'output of said receiver, harnfronic generating'means for deriving'frcmt'he lower frequency oneof said componentsll a harmonic vhaving'a frequency equaly to that of the higher frequencyone f of said` corn-V ponents, 4meansfor vcombining.` said. harmonic with said higher* frequency additively-in one'cir- @uit andsbtactivdy in another circuit, and' twb visual indicators lconnected to said first and second circuits respectively to respond to said resultant voltages.

2. A device for indicating the phase of an alternating voltage with respect to a reference voltage alternating at a frequency harmonically related to that of said first voltage, including in combination a harmonic generator controlled by the lower frequency one of said voltages to produce a harmonic bearing a fixed phase relation to said lower frequency voltage and having a frequency equal to that of the higher frequency one of said Erst-named voltages, means for combining said harmonic voltage with said higher frequency voltage additively in one circuit and subtractively in another circuit, and two voltage amplitude responsive indicating means connected to said first and second circuits respectively to respond to the resultant combined voltage in each of said circuits.

3. A device for providing an indication of the phase relation between two harmonically related components of a complex wave, including in combination lter means arranged to separate said components, Wave shape modication means for producing from the lower frequency one of said components a non-sinsuoidal wave having a harmonic component of a frequency equal to that of the higher frequency one of said first named components and having a xed phase relationship to the lower frequency one of said first named components, lter means for separating said harmonic from said non-sinusoidal wave, and two amplitude responsive indicating devices connected to be controlled by the sum and the diierence respectively of said higher frequency one of said first-named components and said last-named harmonic component.

4. The method of identifying the courses and quadrants of a four course simultaneous radio range which directionally radiates keyed course tone modulated signals and non-directionally radiates a constant phase reference tone modulated signal, comprising the steps of deriving the modulations from said signals, separating the course tone component from the reference tone component, limiting each of said separated components to a constant voltage amplitude, deriving from the lower frequency one of said components a harmonic voltage having a frequency equal to that of the higher frequency one of said components, adding said harmonic voltage to said higher frequency component voltage and producing an indication related to the sum of said voltages, and subtracting said harmonic voltage from said higher frequency voltage and producing a second indication related to the difference of said voltages.

5. The method of indicating the phase of an alternating voltage with respect to a reference voltage alternating at a frequency harmonically related to that of said first voltage, comprising the steps of deriving from the lower frequency one of said voltages a harmonic bearing a fixed phase relation to said lower frequency voltage and having a frequency equal to that of the higher frequency one of said first-named voltages, producing one indication in accordance with the sum of said harmonic voltage and said higher frequency voltage, and producing a second indication in accordance with the difference of said harmonic voltage and said higher frequency voltage.

6. The method of determining the phase relation between two harmonically related components of a complex wave, comprising the steps of separating said components, modifying the wave shape of the lower frequency one of said components to derive a non-sinusoidal wave having a harmonic component of a frequency equal to that of the higher frequency one of said rst named components, separating said harmonic from said non-sinsuoidal wave, and producing indications in accordance with the sum and the difference respectively of said higher frequency one of said first named components and said last named harmonic component.

DAVID G. C. LUCK. 

